package com.glw.sso.platform.common.util;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.nio.charset.StandardCharsets;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

public class RSAEncrypt {
    private static final Map<Integer, String> keyMap = new HashMap<Integer, String>();  //用于封装随机产生的公钥与私钥

    public static final String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCYUa0R4yrZkkFFs7yHjqxUZFVwfgmomn433iU50iVV6RaSrg3j9Av8nsRFB/QNnINOwzByTJTdPObGAasugpud+ge5RqktT4f5rIqvDj3/wBCYbwP6STkqfqu/IZoGlgZQsrbXjKM7c/m+aNOJ38S1cOIOeO44+G0G3dzB+CXRewIDAQAB";
    public static final String privateKey = "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";

    public static void main(String[] args) throws Exception {
        //生成公钥和私钥
        genKeyPair();
        //加密字符串
        String message = "df723820";
        System.out.println("随机生成的公钥为:" + keyMap.get(0));
        System.out.println("随机生成的私钥为:" + keyMap.get(1));
        String messageEn = encrypt(message, keyMap.get(0));
        System.out.println(message + "\t加密后的字符串为:" + messageEn);
        String messageDe = decrypt(messageEn, keyMap.get(1));
        System.out.println("还原后的字符串为:" + messageDe);
    }

    /**
     * 随机生成密钥对
     *
     * @throws NoSuchAlgorithmException
     */
    public static void genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器，密钥大小为96-1024位
        keyPairGen.initialize(1024, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();   // 得到私钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();  // 得到公钥
        String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
        // 得到私钥字符串
        String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
        // 将公钥和私钥保存到Map
        keyMap.put(0, publicKeyString);  //0表示公钥
        keyMap.put(1, privateKeyString);  //1表示私钥
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        return Base64.encodeBase64String(cipher.doFinal(str.getBytes(StandardCharsets.UTF_8)));
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @param privateKey 私钥
     * @return 铭文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str, String privateKey) throws Exception {
        //64位解码加密后的字符串
        byte[] inputByte = Base64.decodeBase64(str.getBytes(StandardCharsets.UTF_8));
        //base64编码的私钥
        byte[] decoded = Base64.decodeBase64(privateKey);
        RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
        //RSA解密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, priKey);
        return new String(cipher.doFinal(inputByte));
    }

}

